Cardiovascular DiseasesNCT00005373
Racial Differences in the Coronary Microcirculation
An observational study of Cardiovascular Diseases and Heart Diseases, run by National Heart, Lung, and Blood Institute (NHLBI).
Trial summary
To study mechanisms of excess coronary ischemia secondary to alterations in autoregulation and arteriolar vasoreactivity in Black Americans with hypertension, varying degree of left ventricular hypertrophy, and angiographically normal or mildly diseased coronary arteries. Read more about this study
- Who is it for?
- Ages Up to 100 years, men only
- Conditions the study is for
- Cardiovascular Diseases, Heart Diseases, Coronary Disease
- How many people
- Not given
- Where
- No sites listed yet
- Study dates
- Sep 1992to Aug 1998
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Up to 100 years
- Men only
- No healthy volunteers
- Child, Adult, Older adult
No eligibility criteria
About this study
To study mechanisms of excess coronary ischemia secondary to alterations in autoregulation and arteriolar vasoreactivity in Black Americans with hypertension, varying degree of left ventricular hypertrophy, and angiographically normal or mildly diseased coronary arteries.
Read the detailed description
BACKGROUND:
Although studies in 1992 with a sufficient number of minority patients were sparse, those available suggested that Black Americans had a higher case fatality from coronary heart disease, but lesser amounts of atherosclerotic coronary artery disease. A possible explanation for this apparent paradox was that myocardial ischemia might be more prevalent with less coronary artery atherosclerosis in Black Americans because of comorbid diseases or differences in coronary physiology. This could be secondary to excess hypertension and left ventricular hypertrophy in Black Americans but might also have been related to intrinsic or acquired differences in coronary artery autoregulation and vasoreactivity leading to depression in coronary blood flow and reserve.
DESIGN NARRATIVE:
The intracoronary Doppler flow velocity guidewire together with quantitative coronary angiography was used to study changes in coronary blood flow in blacks secondary to pharmacologic provocateurs known to induce arteriolar vasodilation. White Americans with similar demographic characteristics and equivalent amount of ventricular hypertrophy and coronary disease were similarly studied in a parallel fashion for comparison. A control group of normal white and Black Americans were studied to detect unexpected intrinsic differences. Both endothelium dependent and independent induction of coronary arteriolar vasodilation were studied. In 25 percent of patients with endothelium dependent defects in arteriolar vasodilation, retesting was performed after intracoronary infusion of L-arginine, the precursor of endothelium dependent relaxing factor. Finally, the possibility of a rightward shift in coronary artery autoregulation in chronic hypertension was investigated. This finding would necessitate that the lower limit of autoregulation occurred at higher diastolic pressures, resulting in a drop-off of coronary perfusion at normal physiologic pressures and ischemia.
The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.
- Conditions
- Cardiovascular Diseases, Heart Diseases, Coronary Disease, Hypertension, Myocardial Ischemia, Hypertrophy, Left Ventricular
- Medical subject headings
- Cardiovascular Diseases, Heart Diseases, Coronary Disease, Hypertension, Myocardial Ischemia, Hypertrophy, Left Ventricular
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 May 2000 (estimated)
- Study startSep 1992
- Study completionAug 1998
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Cardiovascular DiseasesStudies of the same condition, open and under way.
- More trials run by National Heart, Lung, and Blood Institute (NHLBI)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00005373
- Sponsor's protocol ID
- 4267
- Other IDs
- R01HL050262
- Status last verified
- Jul 2000
- First submitted
- 25 May 2000
- Last updated
- 13 May 2016
- Results posted
- No
Publications
Houghton JL, Davison CA, Kuhner PA, Torossov MT, Strogatz DS, Carr AA. Heterogeneous vasomotor responses of coronary conduit and resistance vessels in hypertension. J Am Coll Cardiol. 1998 Feb;31(2):374-82. doi: 10.1016/s0735-1097(97)00505-6.
PubMed 9462582Houghton JL, Carr AA, Strogatz DS, Michel AI, Phillip JL, Kuhner PA, Smith VE, Breisblatt WM. Coronary vasomotor reactivity among normotensive African and white American subjects with chest pain. Am J Med. 1997 Mar;102(3):245-51. doi: 10.1016/S0002-9343(96)00449-4.
PubMed 9217592Houghton JL, Smith VE, Strogatz DS, Henches NL, Breisblatt WM, Carr AA. Effect of African-American race and hypertensive left ventricular hypertrophy on coronary vascular reactivity and endothelial function. Hypertension. 1997 Mar;29(3):706-14. doi: 10.1161/01.hyp.29.3.706.
PubMed 9052885Wood WD. Psychological soundness of women on psychiatry clerkship. J Am Med Womens Assoc (1972). 1980 May;35(5):128, 132. No abstract available.
PubMed 6247382Houghton JL, Prisant LM, Carr AA, Flowers NC, Frank MJ. Racial differences in myocardial ischemia and coronary flow reserve in hypertension. J Am Coll Cardiol. 1994 Apr;23(5):1123-9. doi: 10.1016/0735-1097(94)90600-9.
PubMed 8144778
Study at a glance
From the registry record, last updated by the sponsor on 13 May 2016. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Racial Differences in the Coronary Microcirculation
- ClinicalTrials.gov ID
- NCT00005373
- Acronym / sponsor ID
- 4267
- Conditions
- Cardiovascular Diseases, Heart Diseases, Coronary Disease, Hypertension, Myocardial Ischemia, Hypertrophy, Left Ventricular
- Study type
- Observational
- Recruitment status
- Completed
- Lead sponsor
- National Heart, Lung, and Blood Institute (NHLBI)US National Institutes of Health
- Study start
- Sep 1992
- Study completion
- Aug 1998 (actual)
- First posted
- 26 May 2000 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To study mechanisms of excess coronary ischemia secondary to alterations in autoregulation and arteriolar vasoreactivity in Black Americans with hypertension, varying degree of left ventricular hypertrophy, and angiographically normal or mildly diseased coronary arteries.
Detailed description
BACKGROUND:
Although studies in 1992 with a sufficient number of minority patients were sparse, those available suggested that Black Americans had a higher case fatality from coronary heart disease, but lesser amounts of atherosclerotic coronary artery disease. A possible explanation for this apparent paradox was that myocardial ischemia might be more prevalent with less coronary artery atherosclerosis in Black Americans because of comorbid diseases or differences in coronary physiology. This could be secondary to excess hypertension and left ventricular hypertrophy in Black Americans but might also have been related to intrinsic or acquired differences in coronary artery autoregulation and vasoreactivity leading to depression in coronary blood flow and reserve.
DESIGN NARRATIVE:
The intracoronary Doppler flow velocity guidewire together with quantitative coronary angiography was used to study changes in coronary blood flow in blacks secondary to pharmacologic provocateurs known to induce arteriolar vasodilation. White Americans with similar demographic characteristics and equivalent amount of ventricular hypertrophy and coronary disease were similarly studied in a parallel fashion for comparison. A control group of normal white and Black Americans were studied to detect unexpected intrinsic differences. Both endothelium dependent and independent induction of coronary arteriolar vasodilation were studied. In 25 percent of patients with endothelium dependent defects in arteriolar vasodilation, retesting was performed after intracoronary infusion of L-arginine, the precursor of endothelium dependent relaxing factor. Finally, the possibility of a rightward shift in coronary artery autoregulation in chronic hypertension was investigated. This finding would necessitate that the lower limit of autoregulation occurred at higher diastolic pressures, resulting in a drop-off of coronary perfusion at normal physiologic pressures and ischemia.
The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.
Study design
Who may qualify
- Ages
- Up to 100 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 May 2016.
- Background: PubMed 9462582Houghton JL, Davison CA, Kuhner PA, Torossov MT, Strogatz DS, Carr AA. Heterogeneous vasomotor responses of coronary conduit and resistance vessels in hypertension. J Am Coll Cardiol. 1998 Feb;31(2):374-82. doi: 10.1016/s0735-1097(97)00505-6.
- Background: PubMed 9217592Houghton JL, Carr AA, Strogatz DS, Michel AI, Phillip JL, Kuhner PA, Smith VE, Breisblatt WM. Coronary vasomotor reactivity among normotensive African and white American subjects with chest pain. Am J Med. 1997 Mar;102(3):245-51. doi: 10.1016/S0002-9343(96)00449-4.
- Background: PubMed 9052885Houghton JL, Smith VE, Strogatz DS, Henches NL, Breisblatt WM, Carr AA. Effect of African-American race and hypertensive left ventricular hypertrophy on coronary vascular reactivity and endothelial function. Hypertension. 1997 Mar;29(3):706-14. doi: 10.1161/01.hyp.29.3.706.
- Background: PubMed 6247382Wood WD. Psychological soundness of women on psychiatry clerkship. J Am Med Womens Assoc (1972). 1980 May;35(5):128, 132. No abstract available.
- Background: PubMed 8144778Houghton JL, Prisant LM, Carr AA, Flowers NC, Frank MJ. Racial differences in myocardial ischemia and coronary flow reserve in hypertension. J Am Coll Cardiol. 1994 Apr;23(5):1123-9. doi: 10.1016/0735-1097(94)90600-9.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of Cardiovascular Diseases and Heart Diseases, run by National Heart, Lung, and Blood Institute (NHLBI).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 May 2016. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00005373, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 May 2016; AzTrials last refreshed its copy on 27 Oct 2026.